Manual cranking is the most common and simple technique of providing a mechanical advantage for the operation of devices that impart some kind of required displacement. The manual rotary operation of a crank handle is typically converted via gears or racks or the like to, usually, a linear motion of devices such as gates, doors, sides, roofs, decks, platforms and both flexible and rigid covering systems. It is still common today to use human manual effort to operate such devices. Several typical scenarios where manual rotation is required to operate devices are described below.
Landing gears for articulated trailers allows the raising, lowering and support of the forward end of the trailer in the engagement and disengagement from the prime mover (alternatively known as the tractor or truck) and allows the trailer to be freestanding whilst not in transit. In most instances the trailer itself is decoupled from a prime mover and then re-coupled to either the same prime mover or an another depending on the logistics appropriate to the use.
A typical scenario is where a trailer is delivered to a loading dock for loading. The trailer will typically be loaded up to twenty tons in weight, and in some instances up to twenty five tons, on one trailer. The prime mover positions the trailer in the loading dock. The operator will de-latch the kingpin from the turntable (alternatively known as the fifth wheel) and disconnect the service lines. The operator will then manually lower the legs of the landing gear. First the landing gear will be lowered to ground level in the higher speed selection of the typically two-speed geared landing gear arrangement. Once engaged with the ground the operator generally has no option other than to change to the lower speed selection where the operator will enjoy the significant increase in mechanical advantage afforded by the higher gear ratio. The operator will then with significant effort raise the forward end on the trailer to clear the trailer kingpin from the turntable of the prime mover. Once the trailer king pin is clear of the prime mover turntable the prime mover can be driven clear of the trailer to leave the trailer freestanding. The prime mover is then typically utilized elsewhere in a more productive role than being idle whilst the trailer is loaded.
The trailer will then be loaded which may take a portion of an hour or it may take several days. Once the trailer is loaded a prime mover will then return to the trailer for the removal from the loading dock. In many instances the prime mover will not be the same unit. In such cases the turntable height may not be identical or in other instances due to the poor stability of the ground on which the landing gear rests the trailer may have sunk. In either of these instances the height of the trailer will need to be adjusted to mate with the prime mover. The operator has the onerous task of manually winding the trailer either up or down to the necessary height. Once the trailer is at the correct height for engagement with the prime mover the operator can then locate the prime mover under the trailer, mating the kingpin with the turntable.
To prepare the trailer for transport the legs are manually raised in low speed until they are once again clear of the ground. Having cleared the ground the weight of the loaded trailer is transferred from the landing gear to the prime mover this then allows the landing gear to be changed by the operator to high speed for the legs to be raised to their full height. Raising to full height is necessary to allow ground clearance for traveling both on the road system and in some instances off the road system. Most known landing gear utilizes a two-speed operation and typically the increase in mechanical advantage enjoyed in low speed is in the order of ten to one over the high speed. Even with the advantages afforded by the two-speed operation the time to couple a trailer with a prime mover will find 15 minutes as not atypical. This is particularly so when a trailer is loaded to its limits which generally requires the operator to rest due to the physical fatigue associated with the manual effort required.
There are several teachings of prior art documenting many variations of powered drives that can be added to existing landing gear jacking legs at either the time of installation of the leg or a subsequent time. U.S. Pat. No. 5,451,076 to Burkhead, U.S. Pat. No. 5,299,829 to Rivers, Jr, et al, U.S. Pat. No. 5,050,845 Aline, et al and U.S. Pat. No. 5,004,267 to Busby teach of a pneumatic motor to provide the necessary motive force to rotate the crank shaft (drive shaft) of the landing gear prior art. U.S. Pat. No. 4,466,637 to Nelson teaches of a drive motor such as an electric motor whilst we learn from U.S. Pat. No. 4,097,840 to Chappelle of an electric drive motor. It is noted that all of this prior art has existed for some time yet there is no significant commercialization of this art. The pneumatic teachings have not been accepted due their complexity and expensive nature of their pneumatic componentry. The prior art teachings of electrical motors is cumbersome, weighty and dated in technology. All the prior art tends to be overly complex and does not readily mount up to all commercial landing gear currently available and used within the trucking industry. Most of the prior art requires a strong dependence on the provision of power from the prime mover, that is, the prime mover is required to be coupled to the trailer for the prior art to function.
Another typical scenario of manual operation on a device is where a trailer is used to deliver cereal grain to a holding silo. The trailer is built in the general configuration of a hopper or multiple hoppers so that the grain can be dumped via doors (sometimes known as gates) at the bottom of each hopper within the trailer. When a trailer arrives at a silo the truck driver has to stop the vehicle, disembark from the truck and walk to the hopper door(s). He will then take a separately mounted crank handle and locate it on the spigot (typically hexagonal) of a rotary shaft that is connected to a gear which activates a gear rack, the rack being part of the hopper gate. When the truck driver rotates the crank handle manually he will impart a force to the mechanical arrangement described above which will open the hopper door allowing the grain to be emptied from the trailer.
When the hopper is empty the driver will then return to manually close the hopper door. The loads on the hopper door are considerable resulting in high manual efforts required to operate these doors. Aside from being heavy work, this is also time consuming as each door can only be operated one at a time and the driver is required to be present to provide the manual effort.
In a further typical scenario manual effort is required to expand a section of vehicles or trailers have expanding sections to create more internal space whilst stationary parked or whilst being loaded. While in motion these sections in trailers are retracted. A hospitality trailer may typically have a manual crank arrangement that uses shafts and gears in combination with racks at the four corners of an expanding side to manually wind the side in and out to effectively nearly double the width of a trailer. Such an arrangement can require significant forces, which are manually imparted on the crank to operate such a device. Like a hopper door it can be heavy, time consuming and inefficient use of time for an operator, particularly if there are many sides to be activated.
There have been many attempts to minimize the effort and improve the efficiency of manually wound devices by utilizing powered systems such as hydraulics, pneumatics and electrical power sources. However, known electrical motors, hydraulics and pneumatics used to replace manual winding is cumbersome, weighty and dated in technology. All the prior art tends to be either overly complex, heavy, bulky or does not readily mount up to all commercial applications available and uses. In the transport and related industries, most of the prior art requires a strong dependence on the provision of power from the truck, that is, the truck is required to be coupled to the trailer for the prior art to function.
It is these problems that have brought about the present invention.